The seasoning process should leave a little residual oil but if sometimes I use a little too much oil when I'm doing cast iron maintenance and that happens. Heat it to high and the oil that's left should smoke a little. Run it on high for 10 minutes, let it cool off and wipe it down again. It won't hurt anything to leave a thin coating of oil, but that's a new rig and the best way to season anything is to cook on it!